You have probably heard something about journal impact factors. Are you curious about how these numbers are calculated and if they are even accurate? “The impact factor has been widely adopted as a proxy for journal quality. It is used by libraries to guide purchase and renewal decisions, by researchers deciding where to publish and what to read, by tenure and promotion committees laboring under the assumption that publication in a higher impact-factor journal represents better work, and by editors and publishers as a means to evaluate and promote their journals.
The impact factor for a journal in a given year is calculated by ISI (Thomson Reuters) as the average number of citations in that year to the articles the journal published in the preceding two years. It has been widely criticized on a variety of grounds.” (1)
A new article on impact factors has just been published in the March 2011 NOTICES of the AMS (American Mathematical Society) titled Nefarious Numbers. Authored by a mathematician and mathematics librarian at the University of Minnesota, this article discuses one method in particular which has been used to manipulate the impact factor of a journal upwards, without increasing the quality of the journal.
(1) Notices of the AMS 58: 434-437, Mach 2011